Measuring seed lot purity

What is seed lot purity?

Seed lot purity is a measure of the impurities in a seed batch. These include

  • weed and other crop seed, and
  • inert matter


How is seed lot purity measured?

  1. Select, at random, a sample of the seed. A good sample size is 100g.
  2. Weigh the sample [A].
  3. Remove all of the weed and other crop seeds and the inert matter.
  4. Weigh the weed and the other crop seed matter that had been removed [B]
    1. MeasuringSeedLotPurityB
  5. Compute the weed percentage using this equation:
  6. Weigh the inert matter removed from the sample [C], the percentage inert matter is calculated using the formula:
    1. MeasuringSeedLotPurityC

For more information:

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Prepared by M Gummert with inputs from JF Rickman (2004); updated by M Gummert (2010)